What is a Serpentine Circuit? What role do serpentine traces play in a circuit

It is a wavy or circuitous line, and the snake line has two uses, 1, that is, to increase the length of the line in a limited straight-line distance, which is commonly used in the motherboard and graphics card settings, such as the connection line of the video memory requires each to be the same length, and the short distance is only a snake. 2. The snake line itself can be used as an inductor to increase the current stability.

The above is basically correct, and I will add it again:

Serpentine traces are mainly used in the design of high-speed circuits. Because high-speed circuits need to be designed with signal integrity in mind, data lines need to be of equal length, so some lines must be serpentine to make them as long as others. However, it should be noted that there is a distance requirement between the serpents, and if the distance is too close, your serpentine will not work and the signal quality will deteriorate due to coupling.

There are snake lines on the motherboard, you can take a look, on the back of the main version, there is a continuous S-shape, the main role is to improve its stability and anti-interference.

Deliberately designed so that the signals can arrive at the same time, there are more curved lines near the CPU of the motherboard.

Lines that bend like snakes.

Continuous, curved wiring.

The way the wiring is routed, there is no such circuit.

In order to adjust the delay to meet the system timing design requirements, the designer should have the understanding that the serpentine wire will destroy the signal quality, change the transmission delay, and try to avoid using it when wiring, so the more serpentine wire on a PCB does not mean that it is more "advanced".

For example, the DQS and DQ signal groups in DDR* (DDR1 DDR2 DDR3) require strict isolength to reduce PCB SKEW, so serpentine wires are used.

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Any trace on a PCB that passes through a high-frequency signal will cause a time delay for that signal, and the main purpose of a serpentine trace is to compensate for the smaller delay in the "same set of correlated" signal lines.

These parts are usually no or less than other signals through additional logic processing; The most typical example is the clock line, which usually does not need to go through any other logic processing, so its delay is less than that of other relevant signals.

The equal length of the high-speed digital PCB board is to keep the delay difference of each signal within a range, ensuring the validity of the data read by the system in the same cycle (the delay difference exceeds one clock cycle, the data of the next cycle will be misread).

Generally, the delay difference is not more than 1 4 clock cycles, and the line delay difference per unit length is also fixed, and the delay is related to the line width, line length, copper thickness, and plate structure, but the line is too long to increase the distributed capacitance and distributed inductance, so that the signal quality.

Therefore, the clock IC pin is generally connected to RC termination, but the serpentine trace does not play the role of inductance, on the contrary, the inductance will cause the higher harmonic phase in the rising element in the signal to be dissensitized, resulting in the deterioration of signal quality, so the serpentine line spacing is required to be at least twice the line width, and the smaller the rise time of the signal, the more susceptible it is to the influence of distributed capacitance and distributed inductance.

In order to adjust the delay to meet the system timing design requirements, the designer should have the understanding that the serpentine wire will destroy the signal quality, change the transmission delay, and try to avoid using it when wiring, so the more serpentine wire on a PCB does not mean that it is more "advanced".

For example, the DQS and DQ signal groups in DDR* (DDR1 DDR2 DDR3) require strict isolength to reduce PCB SKEW, so serpentine wires are used.

Serpentine traces are used in high-frequency circuits to create an inductance and in low-frequency, high-current circuits as a current sampling resistor.